Welcome
Welcome to The Koji Fermenteria’s website and wonderful world of koji!
We are London-based small fermenterium specialised in traditional koji making. We make koji in small batch using Japanese koji-buta method (like picture shown above) which enable us to closely monitor its growth.
Lately koji is treated as a rising star among chefs and fermentation enthusiasts all over the world and various new koji making methods are starting to appear. Although every idea has its own merit and of course there is no right or wrong answer, we feel someone needs to strictly follow the tradition based on the understanding of how and why it has been developed. We would like to take this role and contribute to the development of newly born global koji culture.
Let me introduce a little bit about koji. Koji is an intrinsic microbe which has been co-habited with Japanese for millenniums and, without doubt, contributed to the development of umami-based Japanese food culture (it indeed has done numerous amounts of miraculous works on it.. Click here for more detail about koji).
Whereas koji is strongly associated with Japanese food, the principle of it can be applied to any types of cuisine. We believe koji can offer huge potential to open a new dimension to already accomplished many locale cuisines in the world. This is what we want to see and is our motivation to roll out our various activities.

Meet Haruko
Haruko learnt koji making from Nakaji, the author of the highly evaluated “Koji for Life” and is a certified koji specialist (accredited by Nakaji’s Koji Academy). She inherits Nakaji’s koji making approach which is traditional yet flexible.
With the aspiration of making koji as a global culture as well as contributing to boost community welfare with it, she is involved in a various form of activities such as having a stall at farmer’s market, hosting online/offline workshops, participating educational events.
She majored in chemistry in university and was trained as a computer engineer. The influence of her background is clearly evident in her analytical approach in koji making (the glimpse of it is shown in her Instagram posts). She values both scientific evidence as well as sensory experience and is always searching for new subjects of trials and experiments, while carrying out research on new findings and journals. Her curious and inquisitive nature helped her to develop many connections with leading koji/brewing experts in Japan.
Haruko is also a professional translator and translated “Koji for Life” into English
